data(vanDeBunt_students)The data were collected among a group of university freshmen who, except for a few existing relationships (acquaintances from a former school), did not know each other at the first measurement (time=t0). The data were collected at 7 time points. The first four time points are three weeks apart, whereas the last three time points are six weeks apart. The original group consisted of 49 students, but due to 'university drop-outs' and after deleting those who did not fill in the questionnaire four or more times, a group was obtained of 32 students for whom almost complete data are available.
The students were asked to rate their relationships on a six point scale, with response categories described as follows.
NOTE: in the import process, ties are not created for value 0. Also, in the original matrix values ``6 = item non-response, 9 = actor non-response'' These missing data codes were translated to NA values, but not well represented by the conversion to a networkDynamic as we have not set the spec for dynamic missingness yet.
Next to the sociometric data, available individual characteristics are sex, education program, and smoking behavior. Smoking was only allowed in special areas. As a consequence, the 'smokers' had to separate themselves from the 'non-smokers' if they wished to smoke (which they often did during coffee and lunch breaks). Thus, contact opportunities differed between actors because of their smoking behavior. The education program was important because, although all started to study at the same moment, there were three groups, following different courses. During the first months all programs overlapped largely, but after a few months, the programs diverged. Especially the 2-year program was quite different from the other two programs. Therefore, this attribute also gives information on the individuals' contact opportunities. See the references mentioned belo for further information about this network and the actor attributes.
The network contains the following vertex attributes:
As this network was observed at unequal intervals, the net.obs.period attribute provides information on the duration between observation windows.
Van de Bunt, G.G., M.A.J. van Duijn, and T.A.B. Snijders. 1999. Friendship networks through time: An actor-oriented statistical network model. Computational and Mathematical Organization Theory, 5, 167-192.